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Siemens Building Technologies CC1N7865en
HVAC Products 20.11.2002
In that case, the RWF40... operates as a PID / PI controller with a 3-position output
without position feedback signals or, optionally, with a modulating output. By making
use of its self-setting facility, the RWF40... is able to determine the PID / PI control
parameters, or the parameters can be set manually.
Using a potential-free contact, the RWF40... can be switched from the modulating
mode to 2-stage operation.
In the case setpoint shifting is configured, the current setpoint is shifted by an adjust-
able amount. Configuration of setpoint changeover provides changeover between 2
setpoints adjusted on the RWF40... If analog input 2 is configured for an external set-
point, changeover is provided between the setpoint adjusted on the RWF40... and an
external setpoint.
Potential-free contact «K6» can be assigned a number of functions.
Example: Limit value supervision
4 buttons on the unit front are used to operate and program the RWF40... . During op-
eration and programming, the 7-segment displays show the parameter values and pa-
rameter names.
The controller´s standard configuration ex works is such that when connecting a
QAC22 outside sensor, automatic changeover to weather-dependent setpoint shifting
takes place.
The signal delivered by the QAC2... outside sensor may not be fed parallel to sev-
eral RWF40...!
To acquire the actual value, a number of sensors can be connected to the RWF40...
Measurement range
Pt100 / IEC 751 -200...+850 °C (-328...+1562 °F)
Landis & Staefa-Pt1000 / IEC 751 -200...+850 °C (-328...+1562 °F)
Ni100 / DIN 43760 -60...+230 °C (-76...+482 °F)
Ni1000 / DIN 43760 -60...+230 °C (-76...+482 °F)
2-or 3-wire resistance
sensors
LG-Ni1000 -50...+160 °C (-58...+320 °F)
Thermocouples NiCr-Ni / type «K» -200...+1372 °C (-328...+2502 °F)
Cu-Cu-Ni / type «T» -200...+400 °C (-328...+752 °F)
NiCroSil-NiSil / type «N» -100...+1300 °C (-148...+2372 °F)
FeCuNi / type «J» -200...+1000 °C (-328...+1832 °F)
Pt-RhPt / type «S» 0...1768 °C (-32...3214 °F) ¹)
Pt-RhPt / type «R» 0...1768 °C (-32...3214 °F) ¹)
Pt-RhPt / type «B» 0...1820 °C (32...3308 °F) ¹)
0...20 mA scalable -1999...+9999
4...20 mA scalable -1999...+9999
DC 0...10 V scalable -1999...+9999
Linearized standard
signals
DC 0...1 V scalable -1999...+9999
¹) Only RWF40.0X2B97
The power provided for the measuring transducers is DC 24 V / 30 mA.
Feeding a signal to analog input 2, the controller´s setpoint can be influenced. The
influence can be scaled.
The following signals can be used:
- Input signals DC 0...1 V, DC 0...10 V, 0...20 mA, 4...20 mA
- 1 kW potentiometer in a 2-wire circuit
High-fire operation,
modulating control
Binary input 1
(changeover of operat-
ing mode)
Binary input 2 (setpoint
shifting or setpoint
changeover)
Limit comparator
Operation
Weather-dependent
setpoint shifting
nalog input 1 (actual
value sensor)
nalog input 2 (external
setpoint shift or external
setpoint)
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